Solitary Fibrous Tumor of the Pleura: Results

1Mar 2014

Clinical Features The patients were four men between 59 and 69 years old and one woman of 73 years in age. In four patients, the tumor was an incidental finding on a routine chest x-ray film (CXR). The fifth patient had digital clubbing. All the tumors were located in the posteroinferior aspect of the thorax; three were right-sided and two, left-sided. Three patients had functional impairment consistent with previous smoking habits. Only one patient had a history of possible asbestos exposure. Percutaneous biopsies were performed with the patient under local anesthesia and with fluoroscopic guidance (Fig 1). Fine screw needle and large-bore cutting needle biopsies were done in sequence. There were no complications with the procedure. Four patients underwent a thoracotomy, whereas the fifth patient declined surgery. canadian health care mallPathological Features The cytologic smears were not considered diagnostic but pointed to the possibility of a mesenchymal tumor in three out of five cases. The five biopsy specimens, measuring between 2 and 10 mm long, showed a consistent microscopic picture (Fig 2). Small spindle cells characterized by elongated, bland nuclei were interspersed between thick collagen fibers arranged in parallel bands or in a more haphazard fashion. In the four patients who underwent surgery, the tumors were pedunculated and attached to the visceral pleura. They appeared polylobulated with a smooth and glistening surface, weighed from 144 to 1,550 g, and measured from 65X40X30 to 190X150X130 mm. On cut section, the tumors showed a whorled, fleshy appearance, sometimes alternating with more myxoid areas. Focal necrosis and hemorrhagic zones were found in two cases. On light microscopy, all the tumors reproduced the classic picture of solitary fibrous tumor of the pleura. Four cases exhibited only rare mitoses and no cytonuclear abnormalities. One case was focally characterized by a mitotic count in excess of four mitoses per ten high-power fields. By immunohistochemical analysis, all tumors (biopsy specimens and macroscopic specimens) showed a positiv-ity for vimentin and no expression of low molecular weight cytokeratin and desmin. In two cases, the spindle cells were focally positive for muscle-specific actin. The expression of CD 34 depended on the fixative. All formaldehyde-fixed fragments showed a clear-cut positivity, whereas the Allen-Bouin-fixed tissues were mostly negative.

Figure 1. Lateral radiographic view of the cutting needle brought into contact with a tumor located in the posteroinferior aspect of the thorax.